//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19057 SUBJECT: GRB 160223A: Swift detection of a burst DATE: 16/02/23 02:11:02 GMT FROM: David Palmer at LANL C. B. Markwardt (NASA/GSFC), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 01:44:25 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 160223A (trigger=675361). Swift could not slew immediately to the burst due to a Moon observing constraint. The BAT on-board calculated location is RA, Dec 147.584, +9.373 which is RA(J2000) = 09h 50m 20s Dec(J2000) = +09d 22' 21" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure near T+0 s about 30 seconds long, followed by an additional brighter structure peaking at around T+100 for a total duration of ~120 seconds. The peak count rate was ~2200 counts/sec (15-350 keV), at ~110 sec after the trigger. Due to the proximity to the Moon this GRB will not be observable by XRT or UVOT until 22:27UT on Feb 23rd, 2016. Burst Advocate for this burst is C. B. Markwardt (Craig.Markwardt AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19058 SUBJECT: GRB 160223A: GROND optical/NIR afterglow DATE: 16/02/23 07:18:53 GMT FROM: Thomas Kruehler at MPE Garching J. Bolmer (MPE Garching), D. A. Kann (TLS Tautenburg), T. Kruehler, and J. Greiner (both MPE Garching) report on behalf of the GROND team: We observed the field of GRB 160223A (Swift trigger 675361; Markwardt et al., GCN #19057) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPG telescope at the ESO La Silla Observatory (Chile). Observations started at 03:30:41 UT on 2016-02-23, 106 min after the GRB trigger. They were performed at an average seeing of 1".2 and at an average airmass of 1.3. We find a bright, uncatalogued point source within the Swift-BAT error circle at RA (J2000.0) = 09:50:23.34 Dec. (J2000.0) = +09:22:09.0 with an uncertainty of 0".5 in each coordinate. Based on the first 4.4 min of total exposure in g'r'i'z' and 4.0 min in JHK at a mid-time of 03:34:13 UT, we derive the following preliminary magnitudes (all in AB system): g = 17.8 +- 0.1 mag r = 16.9 +- 0.1 mag i = 16.5 +- 0.1 mag z = 16.2 +- 0.1 mag J = 16.1 +- 0.1 mag H = 15.9 +- 0.1 mag K = 15.8 +- 0.1 mag The object fades by 0.4 mag until 04:55 UT on 2016-02-23, so we propose this source to be the optical/NIR afterglow of GRB 160223A. Given magnitudes are calibrated against SDSS as well as 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V) = 0.03 mag in the direction of the burst (Schlafly & Finkbeiner 2011). [GCN OPS NOTE(23feb16): Per author's request, DAK was added to the author list.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19064 SUBJECT: GRB 160223A: Fermi GBM observation DATE: 16/02/23 21:35:50 GMT FROM: Peter Veres at UAH P Veres (UAH), K Toelge (MPE), C Meegan (UAH) and C M Hui (MSFC) report on behalf of the Fermi GBM Team: "At 01:44:22.39 UT on 23 February 2016, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 160223A (trigger 477884666 / 160223072) which was also detected by the Swift/BAT (Markwardt et al., GCN 19057). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 75 degrees. The GBM light curve shows two separate peaks with a duration (T90) of about 117 s (50-300 keV). The time-averaged spectrum from T0-6 s to T0+124 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.96 +/- 0.06 and the cutoff energy, parameterized as Epeak, is 308 +/- 30 keV. The event fluence (10-1000 keV) in this time interval is (1.46 +/- 0.06)E-5 erg/cm^2. The 1-sec peak photon flux measured starting from T0+2.7 s in the 10-1000 keV band is 5.4 +/- 0.2 ph/s/cm^2. A Band function fits the spectrum equally well with Epeak= 282 +/- 45 keV, alpha = -0.94 +/- 0.08 and beta = -2.20 +/- 0.23. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19066 SUBJECT: GRB 160223A: Swift-BAT refined analysis DATE: 16/02/24 07:39:55 GMT FROM: Tilan Ukwatta at LANL C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+581 sec from the recent telemetry downlink, we report further analysis of BAT GRB 160223A (trigger #675361) (Markwardt, et al., GCN Circ. 19057). The BAT ground-calculated position is RA, Dec = 147.603, 9.369 deg which is RA(J2000) = 09h 50m 24.8s Dec(J2000) = +09d 22' 09.3" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 53%. BAT light curve shows two episodes. The first episode starts ~T-10 sec, peaks at ~T+0 sec and ends around ~T+20 sec. The second multi-peaked episode starts around T+70 sec and ends around ~T+120 sec. T90 (15-350 keV) is 127 +- 8 sec (estimated error including systematics). The time-averaged spectrum from T-6.00 to T+143.13 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.34 +- 0.07. The fluence in the 15-150 keV band is 5.0 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+109.95 sec in the 15-150 keV band is 3.1 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/675361/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19072 SUBJECT: GRB 160223A: AbAO optical observations DATE: 16/02/24 20:22:47 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), R. Inasaridze (AbAO), V. Ayvazian (AbAO), A. Volnova (IKI), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of Swift and Fermi GRB 160223A (Markwardt et al., GCN 19057; Veres et al., GCN 19064) with AS-32 (0.7m) telescope of Abastumani Observatory starting on Feb. 23 (UT) 23:51:22. We obtained several unfiltered images of the field. We do not detect afterglow candidate (Bolmer et al., GCN 19058) down to 20.4m. A preliminary photometry of the field is following Date UT start t-T0 Filter Exp. UL (3 sigma) (mid, days) (s) 2016-02-23 23:51:22 0.96907 none 21*120 20.4 photometry is based on nearby stars of SDSS DR9 catalog, Lupton transformation into R. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19074 SUBJECT: GRB 160223A: Swift-XRT afterglow detection DATE: 16/02/25 13:19:17 GMT FROM: Andy Beardmore at U Leicester L.M. McCauley (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Maselli (INAF-IASFPA), B. Sbarufatti (INAF-OAB/PSU) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Swift/BAT-detected burst GRB 160223A (Markwardt et al. GCN Circ. 19066), collecting 8.3 ks of Photon Counting (PC) mode data between T0+109.9 ks and T0+197.1 ks. An uncatalogued X-ray source has been detected inside the Swift/BAT error region, at a location consistent with the GROND afterglow candidate (GCN Circ. 19058). The position of this source is RA, Dec=147.5977, +9.3696 which is equivalent to: RA (J2000): 09:50:23.46 Dec(J2000): +09:22:10.4 with an uncertainty of 6.6 arcsec (radius, 90% confidence). This location is 2.3 arcsec from the reported GROND position. The observed count rate is (1.69 +/- 0.75)e-3 ct s^-1, which corresponds to an observed 0.3-10 keV flux of (3.7 +/- 1.7)e-14 erg cm^-2 s^-1. We cannot determine at the present time whether the source is fading. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00675361. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19079 SUBJECT: GRB 160223A: RATIR Optical and NIR Observations DATE: 16/02/25 17:46:00 GMT FROM: Nat Butler at Az State U Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (GSFC/STScI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), José A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report: We first observed the field of GRB 160223A (Markwardt, et al., GCN 19057) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2016/02 23.15 to 2016/02 23.49 UTC (3.65 to 11.79 hours after the BAT trigger), obtaining a total of 5.04 hours exposure in the r and i bands and 2.26 hours exposure in the Z, Y, J, and H bands. We observed a second time from 2016/02 24.12 to 2016/02 24.49 UTC (26.78 to 35.78 hours after the BAT trigger), obtaining a total of 5.02 hours exposure in the r and i bands and 2.12 hours exposure in the Z, Y, J, and H bands. We detect the afterglow (Bolmer, et al., GCN 19058) cleanly in the first epoch. In comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following magnitudes: r = 18.13 +/- 0.01 i = 17.43 +/- 0.01 Z = 17.37 +/- 0.01 Y = 17.20 +/- 0.01 J = 17.08 +/- 0.01 H = 16.81 +/- 0.01 The source is clearly fading during the first epoch. In the second epoch, we do not detect the source. We obtain the following (3-sigma) upper limits: r > 22.38 i > 22.05 Z > 21.49 Y > 21.44 J > 21.35 H > 21.26 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.